Fluid heater wall



April 5, 1955 R. M. HARDGROVE FLUID HEATER WALL Filed Feb. 2, 1951 INVENTOR F l G. 4 www ATTORNEY United States Patent O FLUID HEATER WALL Ralph M. Hardgrove, Canton, Ohio, assgnor to The Babcock & Wilcox Company, New York, N. Y., a corporation of New Jersey Application February 2, 1951, Serial No. 209,127

4 Claims. (Cl. 122-6) The present invention relates to a fluid heater wall and more particularly to a wall comprising fluid carrying means such as tubes which constitute fluid heating elements. The wall is of a specic construction rendering it especially desirable for use in boilers associated with chemical recovery systems wherein inorganic chemicals contained in a pulp residual liquor are recovered in a usable state by the incineration of the liquor. In a cellulosic pulping process as disclosed, for example, in U. S. Patent 2,354,175 to Leslie S. Wilcoxson, and utilizing a relatively pure magnesium base cooling liquor, the incineration of the liquor is desirably effected under self-sustaining combustion conditions to yield a dry ash consisting mainly of caustic magnesium oxide, while the combustible organic constituents are burned to generate heat for absorption in associated heat recovery apparatus such as a steam boiler. In the recovery unit herein disclosed, incineration of the liquor is to a large extent completed in a furnace chamber which is formed with refractory boundaries so as to maintain suitably high temperature conditions throughout the chamber. In a succeeding zone or passage wherein the combustion of organic constituents continues, the boundaries are desirably formed so as to present refractory surfaces to the burning gaseous stream flowing therethrough. In recovery apparatus wherein such walls or boundaries are formed at least in part by fluid conducting tubes, the refractory shielding surfaces are suitably provided by refractory tile or brick supported on the tubes as hereinafter more fully disclosed.

The various features of novelty that characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of my invention.

Of the drawings:

Fig. l is a sectional side elevation of a fluid heater having walls constructed in accordance with my` invention;

Fig. 2 is an enlarged partial plan section of Fig. l, taken along line 2 2;

Fig. 3 is a fragmentary enlargement of a furnace wall included in Fig. 2; and

Fig. 4 is a vertical section taken along line 4-4 of F.

The fluid heater illustrated in Fig. 1 is a form of vapor generator especially arranged for the recovery of chemicals and heat resulting from the incineration of residual liquor in certain pulping processes including specifically a process employing a relatively pure magnesium base sulphite cooking liquor as disclosed, for example, in U. S. Patent 2,354,175, as hereinbefore mentioned. As shown in Figs. l and 2, the vapor generator includes a furnace combustion chamber of rectangular horizontal and vertical cross section as defined mainly by refractory walls consisting of a front wall 12, a floor 13, a roof 14, and opposing upright side walls 15, of which one only is indicated. The furnace boundaries further include a fluid j cooled rear furnace wall 16 which terminates in spaced relation to floor 13 so as to dene therewith a gas discharge opening or outlet 17. Burners 18 for spraying residual liquor into the furnace are positioned in an upper portion of each side wall 15.

A boiler, or boiler section 20, is arranged rearwardly 2,705,476 Patented Apr. 5, 1955 of chamber 10 to receive the heating gases therefrom. The boiler 20 comprises upper and lower drums 21 and 23, respectively, connected by an upright tube bank 24. Other tubes 25 and 26 having their upper ends connected to the upper drum 21 are extended forwardly and downwardly in separate rows which at the rear of chamber 10 are disposed in horizontally spaced upright planes so as to lie at opposite sides of an open upflow gas pass 27 having a lower end portion in communication with the gas outlet 17. The lower ends of tubes 25 and 26 are connected to a bottom-supported header 28 disposed at an elevation below the lower boiler drum 23 and arranged to receive water therefrom through suitably connected water supply tubes 29. Intermediate portions of tubes 25 are arranged to support and cool the rear furnace Wall 16, While lower portions of certain tubes 25 are suitably displaced in the region of outlet 17 so as to provide adequate gas discharge area therethrough. The front wall of the open pass 27 is thus formed by the rear furnace wall 16 which, in addition to intertube space closure means hereinafter described, comprises rows of refractory tile 31 disposed at opposite sides of the row of tubes 25 and supported thereon in a manner to be .more fully disclosed. The rear wall of pass 27, namely wall 32, similarly comprises rows of refractory tile 31 supported on tubes 26 but disposed at only the forward side thereof, with the bottom rows of tile in the respective walls 31 and 32 arranged at a common elevation directly above the gas outlet 17. At lower elevations, the spaces between tubes 26 are suitably closed by refractory of high heat resistn ance and originally installed as a semi-plastic to provide with wall 32 a continuous gas tight rear boundary of the pass.

The end walls of gas pass 27, namely walls 34 which form continuations of the furnace side walls 15, are also lined with rows of tile 31 supported on side wall tubes 35.

Certain tubes 26 at the rear of gas pass 27 include portions above the upper end of wall 32 which are laterally displaced to provide a gas outlet 36 through which gases are discharged so as to flow into contact with succeeding heating surface including a superheater 37 disposed forwardly of the boiler tube bank 24.

Fig. 2 shows a plan section of wall structures defining the open gas pass 27. Each of the surrounding walls is formed with a row of horizontally spaced upright tubes arranged at center-to-center spacings of about twice the outside diameter of the tubes, and having suitable intertube space closure means therebetween, each wall being faced with refractory tile disposed at the side toward the pass and supported on tubes of the associated wall. The front side of wall 16, at the side toward the combustion chamber 10, is also faced with refractory tile similarly supported on tubes of the wall, each tile or brick in the respective walls having the form of a rectangular prism.

In the construction of rear furnace wall 16, for example, as illustrated in Figs. 3 and 4, certain features are common to other walls 32 and 34 which combine with wall 16 to define the adjoining open pass 27. Referring to wall 16 in particular, each tube 25 is provided with headed studs 41 which are welded thereto in successive circumferentially arranged rows at the side toward pass 27. The studs 41 in adjacent rows are staggered, and each row of studs occupies one-half of the tube circumference, as indicated in Fig. 3. The spaces between studs 41, throughout the horizontal and vertical extent of the wall, are filled with a refractory of high heat resistance and originally installed as a semi-plastic 42 which presents a relatively smooth undulating surface flush with the outer ends of the studs. At intervals within the height of wall 16, tie plates 44 are welded to studs 41 on adjacent tubes throughout the width of the wall, such tie plates being welded to studs in two longitudinal rows, as seen in Fig. 3 and, in a longitudinal direction, being welded to studs in each of about eight or nine circumferential rows.

The tile 31, in their respective rows, and each in the form of a rectangular prism, are supported by metallic V-shaped clips 43 which are rigidly assembled with respect to tubes 25 and which, in horizontal projection as seen in Fig. 3, provide flat plate portions 45 which diverge outwardly from each tube in symmetrical arrangement relative to a plane containing the longitudinal axis of the tube, each clip having a curved base portion 46 which connects the diverging fiat portions 45. At the side toward furnace chamber 10, each clip 43 is welded directly to a tube within an unstudded area of the tube. At the side toward the gas pass 27, curved plates or pads 47 which conform to the perimeter of the stud assembly are welded to the tips of studs 41 in a plurality of rows, and a V-shaped clip 43 is welded at its base 46 to each plate or pad 47.

The tile 31 are supported in horizontal rows and successive tile in each row are separated by a space 48 at a location opposite the centerline of a tube 25. Successive rows of tile are similarly separated by a space 49. The clips 43, which are secured to tubes 25 either directly or indirectly as above described, are disposed in horizontal rows and extend into complementary recesses 51 which are formed in the upper and lower surfaces of the tile, at the inner corners of adjacent tile, directly opposite a tube 25. The inner edges of adjacent tile are beveled, as at 52, throughout the height of the tile between top and bottom recesses 51. As seen in plan, in Fig. 3, the opposing side walls of recesses in adjacent tile are formed with outwardly diverging at portions 53 of substantially the same angularity as the diverging branches 45 of clips 43 whereby, with a clip extending into recesses 51 in adjacent tile, as indicated in Fig. 3, the clip branches 45 are parallel to the recess side wall portions 53 and separated therefrom at each side by a space 54. The contour of each recess 51 is completed by curved side wall portions as indicated.

The horizontal depth of the socket formed by adjacent recesses 51 is substantially equal to or slightly greater than the radial projection of clips 43 from the associated tube 25, while the minimum width of the socket, adjacent the tube, is equal at least to the maximum width of a clip 43 so as to enable the tile to be assembled into their respective positions by movement thereof normal to the wall. After inserting the tile 31 in each row into their respective assembly positions adjacent tubes 25, a soft wooden peg 56 of circular cross section is inserted in space 54 between each clip 43 and each adjacent wall of a top recess 51 so as to act as wedges for retaining horizontally adjacent tile in position until assembly is completed. The remaining space between the clip and the walls of the recess is filled with cement 57 which hardens to a shape conforming to the diverging sides of the clip and thus serves as a lock to prevent outward displacement of the tile, without preventing vertical expansion of the tile. For the tile directly above, the cement is applied to the bottom recesses 51 and the tile pushed into its wall position in which the tile is retained upon hardening of the cement.

As illustrated in Fig. 4, the top and bottom recesses 51 are of equal depths in a Vertical direction while the vertical dimension of a clip 43 is equal to the combined depth of the top and bottom recesses in tile of adjacent horizontal rows. Thus, with a space 49 between adjacent rows of tile, each row of tile is supported on a row of clips 43 which are received within the bottom recesses 51 in tile of the respective rows, while the base of each top recess 51 is separated from the lower edge of a clip 43 by a space 58 which is equal in height to the height of the space 49 between adjacent rows of tile, thereby allowing for relative movement of tile in different rows due, for example, to expansion.

Walls 32 and 34, 34, which form the outer and end walls respectively of gas pass 27, are of substantially the same construction as that portion of the front wall 16 which faces the pass. In rear wall 32, for example, the tubes 26 are spaced in a row and provided with headed studs 41 arranged as shown in Fig. 3 at the side facing pass 27, with refractory of high heat resistance and originally installed as a semi-plastic 42 similarly installed between the studs to form a gas tight wall. Tile 31 are retained in position by V-clips 43 which are welded to plates or pads 47 which in turn are welded to studs 41. The construction of each end wall 34 is substantially the same as described for wall 32 except for the addition of insulation and a casing at the outer sides of tubes 3S.

While in accordance with the provision of the statutes I have illustrated and described herein the best form of my invention now known to me, those skilled in the art will understand that changes may be made in th@ fOIm of the apparatus disclosed without departing from the spirit of the invention covered by my claims, and that certain features of my invention may sometime be used to advantage without a corresponding use of other features.

I claim:

l. A fluid heater wall comprising upright tubes horizontally spaced in a row and formed with projections thereon terminating at a perimeter outwardly spaced from said tubes, refractory tiles disposed in a row outwardly of said perimeter, and means for supporting said tiles comprising pads secured to a plurality of said projections and clip members secured to said pads, adjacent tiles having recesses formed at adjacent corners thereof in which recesses said clip members are received.

2. A fluid heater wall comprising upright tubes disposed at horizontally successive positions in a row, upright refractory tiles forming an upright furnace wall surface and disposed in horizontal rows outwardly of said row of tubes and forming joints between adjacent tiles at locations in front of and medially of the separate tubes of said row, and means for supporting said tiles on said separate tubes comprising clip members individually secured to said tubes at vertically spaced positions and individually having portions diverging outwardly from said tubes, said adjacent tiles at the respective joints having correspondingly vertically spaced recesses in which said clip members are received, said recesses extending only partially into said adjacent tiles in a direction outwardly from said tubes and being formed with opposing side wall recess portions converging inwardly toward said tubes, each recess for a single clip member being formed by two complementary half recesses of adjacent tile, said opposing side wall recess portions being normally laterally spaced from the diverging clip portions to permit the tiles to be moved into their operative positions normally to the plane of the heater wall, said tile supporting means including means interposed relative to the diverging portions of the clips and the adjacent walls of the tile recesses for locking adjacent tiles against outward displacement from the wall.

3. A Huid heater wall comprising a row of upright tubes, refractory tiles of rectangular block formation disposed in a horizontal row parallel to said row of tubes and forming open Vertical joints between adjacent tiles at locations along the respective tubes, said tiles forming a wall surface of the'heater means for supporting said tiles on tubes of said row comprising V-shaped metallic clip members welded to said tubes in vertically spaced horil zontal rows respectively adjacent lower and upper portions of said tiles and each of said clip members having branches diverging toward the exterior of the wall, said adjacent tiles at each of said joints having pairs of coacting and complementary recesses formed in the adjacent lower and upper corners of the vertically adjacent tiles and forming pockets in which the branches of clip members in the respective rows are received, each pocket formed by each pair of complementary recesses having diverging walls substantially parallel to the diverging branches of the clip members said pockets extending only partially into said adjacent tiles in a direction outwardly from said tubes, and means including a solid interposed between and contacting said branches and adjacent walls of said pockets for locking said adjacent tiles against outward displacement from said wall.

4. A uid heater wall comprising a row of upright tubes, refractory tiles of rectangular block formation disposed in adjacent upper and lower horizontal rows parallel to said row of tubes and forming joints between adjacent tiles in each of said adjacent rows at locations along the respective tubes, said tiles forming a wall surface of the heater and means for supporting said tiles on said tubes comprising V-shaped metallic clip members having portions secured to said tubes by welding and having branch portions diverging outwardly into engagement with adjacent tiles in said upper and lower rows, adjacent tiles in each of said upper and lower rows having pairs of coacting complementary recesses therein with each pair forming a unitary pocket in which said branch portions of a clip member are received, and means interposed between said branches and adjacent walls of said pockets for lockilig sald adjacent tiles against outward displacement from t ewa (References on following page) References Cited in the le of this patent UNITED STATES PATENTS Bailey et al Dec. 19, 1933 Sewall et al Feb. 23, 1915 5 Bigelow May22, 1928 Grady Apr. 23, 1935 6 Bailey et al Apr. 30, 1935 Kerr Jan. 21, 1936 Bailey et al. Apr. 12, 1938 FOREIGN PATENTS Great Britain Jan. 18, 1929 Switzerland Apr. 1, 1943 

3. A FLUID HEATER WALL COMPRISING A ROW OF UPRIGHT TUBES, REFRACTORY TILES OF RECTANGULAR BLOCK FORMATION DISPOSED IN A HORIZONTAL ROW PARALLEL TO SAID ROW OF TUBES AND FORMING OPEN VERTICAL JOINTS BETWEEN ADJACENT TILES AT LOCATIONS ALONG THE RESPECTIVE TUBES, SAID TILES FORMING A WALL SURFACE OF THE HEATER MEANS FOR SUPPORTING SAID TILES ON TUBES OF SAID ROW COMPRISING V-SHAPED METALLIC CLIP MEMBERS WELDED TO SAID TUBES IN VERTICALLY SPACED HORIZONTAL ROWS RESPECTIVELY ADJACENT LOWER AND UPPER PORTIONS OF SAID TILES AND EACH OF SAID CLIP MEMBERS HAVING BRANCHES DIVERGING TOWARD THE EXTERIOR OF THE WALL, SAID ADJACENT TILES AT EACH OF SAID JOINS HAVING PAIRS OF COACTING AND COMPLEMENTARY RECESSES FORMED IN THE ADJACENT LOWER AND UPPER CORNERS OF THE VERTICALLY ADJACENT TILES AND FORMING POCKETS IN WHICH THE BRANCHES OF CLIP MEMBERS IN THE RESPECTIVE ROWS ARE RECEIVED, EACH POCKET FORMED BY EACH PAIR OF COMPLEMENTARY RECESSES HAVING DIVERGING WALLS SUBSTANTIALLY PARALLEL TO THE DIVERGING BRANCHES OF THE CLIP MEMBERS SAID POCKETS EXTENDING ONLY PARTIALLY INTO SAID ADJACENT TILES IN A DIRECTION OUTWARDLY FROM SAID TUBES, AND MEANS INCLUDING A SOLID INTERPOSED BETWEEN AND CONTACTING SAID BRANCHES AND ADJACENT WALLS OF SAID POCKETS FOR LOCKING SAID ADJACENT TILES AGAINST OUTWARD DISPLACEMENT FROM SAID WALL. 